Well, if you're using indicator, you get a relatively large indicator error - for example:
If you are doing a titration for NaOH and HCl and use bromothymol blue, the pH range is 6.0-7.6 - the colour change occurs before pH of 7, where you expect perfect titration to be approximately. Therefore, you get something called "indicator error".
If you use a pH meter, you don't have that problem.